ABSTRACT
Objective To investigate the impact of AG490 on the blood-brain barrier (BBB ) permeability and the expression of interleukin-6 (IL-6 )and tumor necrosis factor-α(TNF-α)after traumatic brain injury (TBI)in rats. Methods A total of 144 healthy male SD rats were randomly divided into a control group,a trauma group,and an AG490 intervention group (n=48 in each group). The rats in each group were redivided into four subgroups (4 h,1 d,3 d,and 7 d subgroups)according to the time points after cerebral injury (n=12 in each subgroup). A brain trauma models were induced by hydraulic shock method. Evans blue was used to determine the changes of the BBB permeability after cerebral injury in each group. Real-time fluorescence quantitative PCR was to detect the expression levels of TNF-αand IL-6 mRNA in rat brain tissue. Immunohistochemistry was used to detect the expression of human phospho tyrosine kinase (P-JAK2). Results (1)The permeability of BBB:The permeability of BBB increased at 4 h,1 d,3 d and 7 d after brain injury in the trauma group (Evans blue permeation:10. 4 ± 1. 2,16. 0 ± 1. 4,22. 3 ± 2. 0,and 8. 4 ± 0. 9μg/g,respectively). Compared with the control group, there were significant differences (all P<0. 01). The Evans blue permeation of the AG490 intervention group were 9. 1 ± 1. 0,12. 8 ± 1. 1,17. 5 ± 1. 4 and 7. 1 ± 0. 8μg/g,respectively at each time point,and they were all significantly lower than those of the trauma group (all P<0. 01). (2)The expression of IL-6 and TNF-α mRNA:The expression levels of IL-6 mRNA and TNF-α mRNA at 4 h,1 d,3 d and 7 d after traumatic brain injury in the trauma group were 2. 31 ± 0. 35,2. 73 ± 0. 35,3. 32 ± 0. 29,2. 14 ± 0. 24 and 7. 46 ± 1. 18,9. 42 ± 1. 54,13. 76 ± 1. 89,and 6. 28 ± 1. 00,respectively,they were all significantly higher than those of the control group (all P<0. 01). The expression levels of IL-6 mRNA and TNF-α mRNA of the AG490 intervention group were 1. 14 ± 0. 22,1. 54 ± 0. 23,1. 94 ± 0. 32,1. 26 ± 0. 21 and 5. 57 ± 0. 88, 7. 78 ± 1. 02,11. 51 ± 1. 29,and 5. 05 ± 0. 97,respectively,they were all lower than those of the trauma group,but they still higher than the control group. There were significant differences (all P<0. 01). (3 )The expression of P-JAK2:The expression levels of P-JAK2-positive cells at each time point after traumatic brain injury in the trauma group were significantly higher than the control group (all P<0. 01),they were 17. 4 ± 2. 7,56. 2 ± 6. 7,26. 1 ± 5. 4,and 15. 3 ± 2. 5,respectively;those of the AG490 intervention group were 12. 2 ± 1. 4,41. 5 ± 4. 6,19. 4 ± 4. 1,and 9. 6 ± 2. 0,respectively,they were all lower than those of the trauma group,but still higher than the control group. There were significant differences (all P<0. 01). Conclusion During the acute phase after TBI,AG490 may activate the factor signaling pathways by inhibiting the non-receptor tyrosine kinase/signal transduction and transcription,significantly inhibit the expression of brain tissue inflammatory cytokines IL-6 IL-6 and TNF-α,reduce the BBB damage,and help to reduce secondary brain injury.